Abstract
Respiratory syncytial virus (RSV) is the leading cause of severe respiratory infections in children. In many countries, changes in RSV hospitalizations have occurred during COVID-19 restriction, with alterations in annual pre-pandemic trends. The objective of this retrospective study was to describe the epidemiology of RSV during the pandemic in Spain (2018-2021) through population-based estimates of hospitalization in children <2 years old. A total of 56,741 hospital discharges were identified with a 2.2% decrease between the beginning and the end of the COVID-19 pandemic resulting in a hospitalization rate of 1,915.89 (95% CI = 1,900.13-1,931.65) hospitalizations per 100,000 children. During the four-year period, a total of 34 deaths were recorded (males 63%, females 37%). The average annual cost to the National Health-Care System of bronchiolitis requiring hospitalization was €49,6 million with an average hospitalization cost per case of €3,054. RSV is a very frequent virus associated with community-acquired pneumonia (CAP) in children under 2 years old, so future preventive interventions should target this age group including vaccination programs.